Hi,
Two comments:
On Tue, 7 Dec 2010, Kevin Hilman wrote:
> commit 0d8e2d0dad98a693bad88aea6876ac8b94ad95c6 (OMAP2+: PM/serial:
> hold console semaphore while OMAP UARTs are disabled) added use of the
> console semaphore to protect UARTs from being accessed after disabled
> during idle, but this causes problems in suspend.
>
> During suspend, the console semaphore is already held by the time we reach
> the OMAP suspend path, so the try_acquire_console_sem() will always fail and
> suspend will be aborted.
>
> To fix, introduce a check so the console semaphore is only attempted
> during idle, and not during suspend.
>
> Cc: Paul Walmsley <paul@xxxxxxxxx>
> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
> ---
> Applies to Tony's omap-fixes branch.
>
> arch/arm/mach-omap2/pm34xx.c | 24 ++++++++++++++++++------
> 1 files changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 0ec8a04..122ef3c 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -50,6 +50,19 @@
> #include "sdrc.h"
> #include "control.h"
>
> +#ifdef CONFIG_SUSPEND
> +static suspend_state_t suspend_state = PM_SUSPEND_ON;
> +static inline bool is_suspending(void)
> +{
> + return (suspend_state != PM_SUSPEND_ON);
> +}
> +#else
> +static inline bool is_suspending(void)
> +{
> + return false;
> +}
> +#endif
> +
> /* Scratchpad offsets */
> #define OMAP343X_TABLE_ADDRESS_OFFSET 0xc4
> #define OMAP343X_TABLE_VALUE_OFFSET 0xc0
> @@ -387,10 +400,11 @@ void omap_sram_idle(void)
> }
>
> /* Block console output in case it is on one of the OMAP UARTs */
> - if (per_next_state < PWRDM_POWER_ON ||
> - core_next_state < PWRDM_POWER_ON)
> - if (try_acquire_console_sem())
> - goto console_still_active;
> + if (!is_suspending())
> + if (per_next_state < PWRDM_POWER_ON ||
> + core_next_state < PWRDM_POWER_ON)
> + if (try_acquire_console_sem())
> + goto console_still_active;
This same is_suspending() test needs to be applied to the
release_console_sem() later in the pm34xx.c, otherwise the console
semaphore will be released before the Linux suspend code expects it to be.
Also, I'd assume that a similar patch to the above needs to be applied to
pm24xx.c.
- Paul
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
